Safety device for electric switches



J, F. BURNS. SAFETY DEVSCE FOR ELECTRIC SWITCHES.

APPL|CATION FILED AUG.2, 1917.

Patented Nov. 2, 1920..

3 SHEETSSHEET 1- J. F. BURNS.

SAFETY DEVICE FOR ELECTRIC SWITCHES. APPLICATION FILED AUG-2, 1917.

1,357,762. Patented Nov. 2, 1920.

3 SHEETS-SHEET 2- I. F. BURNS.

SAFETY DEVICE FOR ELECTRIC SWITCHES. APPLICATION FILED AUG.2, I917.

1,357,762, Patented Nov. 2, 1920;

3 SHEETS-SHEET 3.

UNITED STATES PATENT OFFICE.

JAMES F. BURNS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO V. V. FITTINGS COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYL- VANIA.

Application filed August 2, 1917.

- To all whom it may concern:

Be it known that I, James F. BURNS, a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented Safety Devices for Electric Switches, of which the following is a specification.

One object of my invention is to provide an electric switch and inclosing casing or box therefor, with a relatively simple and substantial attachment whereby the lid or cover of said box is maintained in a locked condition preventing access to the switch until the latter has been moved to a fully opened position.

A further object of the invention is to provide an attachment of the character above indicated which shall include means for preventing the switch being moved to its closed position until the lid or cover of the box has been closed ;the invention in its preferred form also contemplating means whereby said switch may be locked in its open position with the lid or cover closed.

These objects and other advantageous ends I secure as hereinafter set forth, reference being had to the accompanying drawings, 1n which,

Figures 1 and2 are respectively a front elevation and a bottom view of a switch box and switch constructed according to my invention;

Fig. 3 is a side elevation of the structure shown in Figs. 1 and 2;

Fig. i is a bottom View, showing the cover in a partly raised position;

Fig. 5 is a plan of the switch box and switch with the cover removed;

Fig. 6 is a vertical section on the line 6-6, Fig. 1;

Fig. 7 is a perspective view illustrating one of the switch operating rods and its associated locking mechanism;

Fig. 8 is a transverse section on the line 8-8, Fig. 6;

Fig. 9 is a vertical section on the line 9-9, Fig. 8 showing one of the switch operating rods in its outer position;

Figs. 10 and 11 are two sections similar to those of Figs. 8 and 9 respectively, showing the various parts in the positions occupied when the-lid of the switch box is opened; and

Fig. 12 is a vertical section similar to Fig.

Specification of Letters Patent.

Patented Nov. 2, 1920..

Serial No. 184,145.

attachment of conductors and also having clips to which are pivoted the blades 7, 8 and 9, which with a connecting cross bar 10 of insulating material, constitute the movable part of the switch.

Also mounted on the base 3 are three terminals 11, 12 and 13, including clips for the reception of the blades 7, 8 and 9, and also including other clips or holders for the reception of cartridge fuses. A second set of terminals 14, 15 and 16 is provided on the switch plate 3, and each of these includes a clip for the reception of the second end of a cartridge fuse whose opposite end engages one of the clips 11, 12 or 13 as the case may be. Each of these terminals also includes a binding screw for the attachment of a conductor and it is to be understood that suitable openings are provided in the front and rear ends of the box 1 to permit of the entrance thereto of the six conductors designed for connection to the terminals 4:, 5, (3 and 14., 15, 16.

For shifting the position of the movable switch member 7-10, from its open to its closed position or vice versa, there is connected to the cross bar 10 a pair of rods 17 and 18 which pass through tubular guides 19 and 20 respectively at the front end of the box 1 and are connected at their outer ends by a transversely extending handle 21 of insulating material. Obviously without departing from my invention, one of the above noted operating rods may be dispensed with,

but where the movable switch member is of ance orinner part of its length, a smaller diameter portion 23. lln addition I provide on the small diameter part adjacent the inner end of the large diameter part 22 a collar 24. Obviously said rod is made in large and small diameter portions as a matter of convenience, since its essential feature resides in the provision of a shouldered recess, preferably of annular form, with a collar or equivalent projection adjacent thereto.

While as shown in Fig. 5, the second rod 18 is formed in two parts of different diameters, this is immaterial for purposes of my invention.

As illustrated in Fig. 4, the cover 2 of the switch box has a bottom portion 25, with slots or recesses 26 and 27 formed in its edge designed to permit of the passage of the latter below the switch operating rods 17 and 18, and it is noted that the first of these slots has a relatively narrow entrance whose width is sufficient to permit of the passage of the part 23 of the rod 17, but too narrow to pass the part 22. The latter however is of a diameter sufliciently small to permit of its sliding longitudinally through the larger part of this slot.

Mounted 'within the front end of the box, immediately adjacent the rod guide 19, is a bracket or supporting structure 28, illustrated as in the form of a casing held to the front of said box by a pair of bolts 29 and 30. This casing is in the form of an inclosing structure projecting above the top of the front of the box and having through its projecting portion a relatively large opening 31 for the passage of the rod 17 and its collar 24.

Within the casing provided by said structure 28 is a locking plate 32 pivotally mounted on the bolt 30 and at all times so acted on by a spring 33 as to tend to swing upwardly toward the switch operating rod 23. The outer end of said plate has a flattened or laterally extended head 34, immediately above which there is provided an opening 35 through the casing 28 for the passage of a pin or bolt 36 rigidly mounted in the front part of the cover 2 ;-the arrangement being such that the act of moving said cover to its closed position causes said pin to enter the opening 35 and by engaging the head 34, swing the plate 32 downwardly against the action of the spring 33, thereby withdrawing a projecting portion 37 of said plate from the vicinity of the switch operating rod 23.

As shown in Figs. 2 and 4, the cover has on one of its side edges a projecting perforated lug .38 designed to have its perforation in line with that of a second lug 39 projecting from the box 1 when said cover is closed, so as to permit of the hasp ofa padlock 40 being passed" through said perforations in order that the cover may be locked in its closed position. V

Withthe above described-arrangement of parts, it will be understood that whenever the cover is in its open position and the movable switch member is likewise open, the latter is locked in such open position, since as shown in Figs. 1.0 and 11, the projection 37 of the'locking plate 32 is maintained by the spring 33 in engagement with the small diameter portion 23 of the switch rod 17 to the rear of the collar' 24 and obviously any inward movement of the switch handle is impossible after said collar strikes the projection 37 Since the supply mains for the switch are connected to the terminals 4, 5 and 6, fuses may be now safely placed between or removed from engagement with the two sets of terminals 11, 12 and 13 and 14, 15 and 16;the operator being additionally protected by the provision of a plate 41 of insulating material fastened to the cross bar 10 of the movable switch member and of such dimensions as to completely cover the three switch blades 7, 8 and 9, except where it is cut away to permit of engagement of said blades by the clips 11, 12 and 13.

When the cover 2 is moved to its closed position, in which it is normally held by a spring catch 42 engaging a projection such as a screw head 43 on the box, the pin 36, by engaging the head 34 of the locking plate 32, forces the latter with its projection away from the switch rod 17 so that it is possible by pressing in upon the cross bar 21, to move the switch blades 7, 8 and 9, into electrical engagement with the terminals 11, 12 and 13 and thus to close the switch.

When the parts are in these positions however, it is not possible to open or raise the cover, since as will be obvious from Figs. 4, 5 and 6, the large diameter portion 22 of the operating rod 17 has been entered in the larger portion of the slot 26 in the cover and cannot be moved upwardly with the latter because of its passage through the guide 19. There is no possibility therefore of removing the fuses or of otherwise tampering with the switch until the blades thereof have been mowed to their fully opened position and the larger portion of the operating rod 17 has been replaced in the slot 26 of the cover by the smaller diameter part thereof,--when the cover may be raised.

If it be desired to lock the switch blade in its open position when the box cover is closed, this is done by first drawing the handle 21 outwardly as far as possible to open the switch, then opening the cover and finally by drawing the handle with the switch blade still farther out, thus causing the collar 24 on the rod 17 to move from a position immediately adjacent the locking plate 32 (Figs. 10 and 11), to the position shown in Fig; 12 within the guide 19. Thereafter when the cover is again closed 1 omes l J. close the raise cover, more the handle inwardly nnoi collar 2 1e locking plate 32,

i move the cover o in which said loclring the pin 36. The s cc to be moved s it being noted that closed been is depressed handle is to close s ows t the positions l when the s i "do is loclred L i position 9 shows the dle has been "r 1 its closed EEO.

.L J.- to clear the open the switch-cont ch has been rnlly c to ordinarily clo e said,

DOSS

switch r'itil t e cover has closed,

urther vable switch inernbe be convenien .y locked in its open and retained l. The combination of a box ha cover movably mounted thereon; an eiectrlc switch seid box; a rod for ope said switch mounted to be longitno movable through an open sided opening in the cover having an enlargement taining the cover closed until the open, said being formed to pass out of si e o the opening in the over i n in which the by locking i on of a body w h an opening na entrance; e and an operatin o the switch 5 t rough the ope inner having porti through entra e of is}. positioned to lie n the cover ezrcep when the switch is ope 3. The combination of e her ha Mg a cover provided with a recess in one edge 1313- having a main portion and a narrow side entrance thereto; an electric switch in said box; and an actuating member for the switch operative in said recess of the cover and having a portion locking the latter closed when the switch is closed and ines to prevent opening of eluding a relatively narrow portion positioned to pass through the narrow side entrance of the recess in the cover to permit opening of the latter only whenthe switch is open. I

4. The combination of a box having a cover provided with a recess in one edge having connected wide and narrow portions; on electric switch in said box; an operating member for the switch having a part operative in the side portion or the recess of the cover and i formed to lock said cover closed when the switch is closed also including a relatively narrower portion positioned to pass laterally through the narrow part of the recess to allow opening of t cover only when the switch is in its open position.

5., T e combination of a box having ed with an opening one edge i movement eluding a narrow portion capable of o through the ens nice of the openi cover also having a wider poi ion inca able o passing said entrance but slidthe body of the opening the able narrow of said member being plceoi lie adjacent the entrance to the ope of the cover only when the switch is onenu 6. The combination or a box havin a cover hinged thereto and provided in I edge with an opening having relatively narrow entrance; a switch in the box; and at least one operating rod for said switch held from bodily lateral inoyeinent'hut longitudinally guided-in the box and having a portion slidable in the opening thereof but incapable of passing. the entrance to said opening, said rod also having a part of a width capable 01 passing through entrance to the opening in the cover placed as to lie adjacent said openiwhen the rod'is in a position correspon the open position of the switch,

7, The combination of a be having cover; a switch in said hon having K l crating rod including a collar and two "aortions of di lerent widths, the cover recess with a narrow entrance capable of receiving the narrow part oi. the red but i capable of passing the wider portion ereoi with a locking bolt onthe box actested by the cover and positioned to engage the collar to hold the switch operating rod from movement as long as the cover is i a re atively narrow entranceg.

5 t emes venting longitudinal movement of said member and closure of the switch when said cover is closed. v

9. The combination of a box having a cover; a switch in said box; with a longitudinally movable operating member for the switch having an abutment cooperating with the cover to prevent movement of said member and closure of the switch when the cover is closed.

10. The combination of a box having a cover; a switch in said box; an operating member for the switch having an abutment cooperating with the cover to prevent closure of the switch when the cover is closed; anda lock on the box aisc cooperating wit said abutment to prevent closure, of the switch under predetermined conditions when the cover is opened.

11. The combination of a box having a cover; a switch in said box; an operating member for the switch having an abutment cooperating with the cover to prevent closure of the switch when the cover is closed; with a lock on the box also cooperating with said abutment and operative by the cover for preventing closure of the switch under predetermined conditions when the cover is opened.

in wltness whereoi I affix my signature.

JAMES F. BURNS, 

